This is a proposal for the development of an inexpensive software accessory which enhances microcomputer access for the partially sighted. The software magnifies selected portions of a computer screen, enabling a person with low visual acuity to use standard personal computers and software packages without special equipment or modifications. By making standard products available, this approach creates an unprecedented potential to open the doors for the partially sighted to the mainstream of personal, educational, and employment opportunities. The primary objective of Phase I is to design and develop, in a laboratory setting, a working model embodying these concepts. Subjects representative of various partially sighted populations play a major role in testing and refining this prototype through systematic trial, observation, and feedback. Phase I also includes a preliminary assessment of the concept's usability and potential.